In this screengrab from a webcast, Microsoft CEO Steve Ballmer speaks at an event in San Francisco on Monday to highlight Windows Phone 8. / USA TODAY

by By Scott Martin, USA TODAY

by By Scott Martin, USA TODAY

SANTA CLARA, Calif. -- CEO Steve Ballmer sat down last night for an interview in the heart of Silicon Valley, cheerleading for all things Microsoft in the backyards of Apple and Google.

The Churchill Club interview came at a turbulent time for Microsoft. Now the mobile underdog to these rivals, the software giant faces an uncertain future as its next-generation Windows 8 gets underway in a bid to revive the PC market. If that weren't enough, Microsoft Windows division president Steven Sinofsky -- widely seen as Ballmer's heir apparent -- this week left the company in a cloud of mystery.

Interviewer Reid Hoffman, co-founder of LinkedIn, wasted no time in asking Ballmer how Microsoft will move on without 23-year veteran Sinofsky.

"The new team is fantastic. Maybe a little less well known. But the lady taking over the product development ... has been a driver behind the vision and will continue down the path," said Ballmer.

Sinofsky was a controversial figure known to deliver on huge projects. He was the driver behind both Windows 7 and Windows 8, but he was also widely reported to be at odds with some executives.

His unexpected departure raises questions about his performance on Windows 8 and the company's mobile future.

"All the Steve Jobs comparisons aside, my concern now is that the only guy (Sinofsky) that could raise their mobile perspective is gone now," says Gartner analyst Carolina Milanesi.

Last month, Microsoft's board disclosed in an SEC filing that it awarded Sinofsky just 60% of his bonus, citing a decline in Windows revenue. Ballmer was awarded less than half his bonus.

What's clear is that people's computing habits have changed. In this post-PC era, Hoffman said Apple and Google's strategies are clear, but asked, "what's the Windows' strategy in this?"

Ballmer replied that Microsoft needs to stake out a position in the mobile market. "The ecosystem of Android is a little bit wild ... it's maybe in way that's not always in the consumer's best interest." Apple's is quite "high priced" and "controlled," he said, adding a "best of both worlds" is available to Microsoft.